One way to characterize the manner in which information is recorded to and/or read from a rigid, magnetic, computer-readable storage medium (e.g., a disk) is the manner in which the magnetic recording head interfaces with the disk. Contact recording has at least been proposed to place the head and disk in direct physical contact when exchanging signals therebetween. Theoretically this maximizes the performance of the head and disk at least in relation to reading information from and writing information to the disk. Other issues have kept contact recording systems from realizing commercial success. Constant contact between the head and disk presents both wear and contamination (e.g., through generation of particulates) issues which need to be addressed by the disk drive design. Heat generated by the continuous contact between the head and disk during disk drive operations can also have an adverse effect on the accuracy of the exchange of information between the head and disk (e.g., via thermal transients or asperities). Frictional forces from the contact between the recording head and disk can also cause data transfer problems in the form of track misregistrations, as well as bit shift or jitter caused by suspension and/or air-bearing resonance excitations.
Another approach which has been utilized in commercial disk drive designs is for the magnetic recording head to fly above the surface of the rigid, magnetic disk. Typically the magnetic recording head includes a slider with a magnetic recording and/or writing element(s) carried thereby. One or more air-bearing surfaces are included on the lower surface of the slider which project at least generally toward the disk. These air-bearing surfaces are shaped/oriented on the slider body so that the boundary layer of air which is carried by the rigid disk during rotation thereof is compressed and forced to flow underneath the slider. Rotation of the disk in excess of a certain velocity will generate sufficient forces on the air bearing surfaces to lift the slider above the surface of the disk toward which the air-bearing surfaces at least generally project.
Relatively significant development efforts have been directed to the design of the air-bearing surfaces of sliders of the flying type. The problems which have been addressed by these efforts have not been simply to realize flying of the slider in spaced relation to the disk, but instead to considerations such as attempting to accurately control the fly height or to achieve a consistent fly height. Another area of focus has been to attempt to minimize the spacing between the head and disk during disk drive operations without actually having any significant contact which can have adverse effects on data transfer operations, as well as the operability of the disk drive or components thereof. Current state-of-the art, commercially available disk drives with MR/GMR heads operate with an average fly height of about 10 nanometers. However, this does not correspond with a 10 nanometer spacing between the magneto-resistive recording element and the disk. Pole-tip recession typically adds another 3–5 nanometers to the actual spacing being the recording element and the disk, as does the carbon overcoat which is typically included on the bottom surface of current flying sliders. Reducing the spacing between the flying head and rigid, rotating disk would be desirable to realize higher bit and track densities.